(a) Field of the Invention
The present invention relates to a method of recovering the heat possessed by the high-temperature combustion waste gas exhausted from a glass tank furnace, which method comprises contacting said combustion waste gas with a powdery substance in suspension state thereby to heat said powdery substance and heating the air for combustion and/or the raw materials for glass with the thus heated powdery substance.
(B) Description of the Prior Art
The conventional glass tank furnace has a structure wherein, on both sides of the melting furnace, there are disposed bilateral regenerators containing checker bricks piled up so as to leave spaces therebetween and arranged in parallel with heavy oil burners respectively. The flames are jetted from the heavy oil burners arranged on one side and also the air for combustion which has passed through the regenerators on the same side is blown into the melting zone, while into the regenerators of the other side is drawn the high-temperature combustion waste gas simultaneously therewith. The blowoff and suction are alternately performed on the two sides of the furnace at regular intervals.
The air for combustion is usually preheated in the course of passing through the spaces between the checker bricks of the regenerators, previously heated with the combustion waste gas, immediately before it is blown into said melting furnace. The preheated air for combustion is the source of oxygen for burning the heavy oil or the like in the melting furnace.
However, according to the above described method of preheating the air for combustion utilizing regenerators, the heat held by the regenerators diminishes with the passage of time because the heat is gradually withdrawn by the air for combustion. Accordingly the temperature of the preheated air for combustion gradually is reduced thereby rendering it difficult to supply air for combustion which is preheated at a constant temperature. The resulting thermal fluctuation of the air for combustion is undesirable from the view point of efficient operation of the melting furnace for glass. And, what is more, the cost of construction of the regenerators accounts for a great portion of the total expenditure for a glass tank furnace.
With respect to the raw materials for glass, various methods of preheating same have hitherto been proposed, but none of them has proved satisfactory. As a consequence, application of the conventional method of supplying low-temperature raw materials for preparing glass to a melting furnace and melting them by the use of heavy oil or the like remain unchanged. However, this conventional method is not desirable from the view point of economy of fuel as well as efficient melting of glass.